EFFECTS OF ADJUVANTS, SOIL MOISTURE AND ATRAZINE ON THE ACTIVITY OF NICOSULFURON ON LARGE CRABGRASS (DIGITARIA SANGUINALIS)

摘要

Greenhouse experiments were conducted to examine the influence of adjuvants, soil moisture stress and atrazine on the performance of nicosulfuron on large crabgrass (Digilaria sanguinalis L). Nicosulfuron was applied alone or in combination with 0.5% (v/v) Sun oil, 0.5% (v/v) Agrirob, 0.25% (v/v) Genapol, 0.1% (v/v) Lissapol and 0.25% (v/v) Silwet L-77. All adjuvants except Silwet L-77 improved the performance of nicosulfuron. A reduced efficacy was found when nicosulfuron was mixed with Silwet L-77. Three levels of soil moisture stress (none, moderate and high) were obtained by stopping watering of the pots 0, 3 and 6 days before treatment, respectively. The results demonstrated that water stress increased the ED_(50) dose irrespectively of whether nicosulfuron was applied alone or in mixture with 0.5% (v/v) Lissapol. Atrazine at 200 and 400g ha~(-1) mixed with nicosulfuron at 40g ha~(-1) did not reduce the activity of nicosulfuron on large crabgrass. It was concluded that atrazine at the rate used in the present experiment did not antagonise nicosulfuron.